Party-line telephone



Nov. 16 1926.

G. H. BRYANT ET AL PARTY LINE: TELEPHONE 2 Sheets-Sheet 1 @rofl Filed June 17, 1924 1N VENTORS ATTORNEYS Nov. 16 1926.

G. H. BRYANT ET AL PARTY LINE TELEPHONE Filed une 17, 1924 2 Sheets-Sheet. 2

FIG.

ABF

lNvENToRs Patented Nov., l, 1926.

BATEGNT QFFICE,

GEORGE HENRY BRYANT, BENJAMN BERTIE JOHNSON, AND RICHARD GRANT VAN- NECK, OF LONDON7 ENGLAND, ASSGNORS TO THE RELAY AUTOMATIC TELEHONE CGIT'IEANY, LMETED. OF LONDGN, ENGLAND. y

'EAETY-LENE TELEPHONE.

Application filed June 17, 1924, Serial No. 729,574, and in Great Britain June 26, 1923.

Our invention relates to improvementsl in lock-out party lines and has for its object to provide a cheap7 simple and reliable party line apparatus.

Our invention especially relates to that type of system in which the subscribers lines are commoned to a single junctionat a small local exchange and in which local connections are performed by automatic ap 3aratus controlled by an operator at the other end of a junction to distant or main exchange? while distant or interoiiice connections are completed by the operator in the usual manner. Such small exchanges are frequently termed village exchanges.

According toV our invention we provide party line apparatus whereby any party to the line can obtain access to the linetto the exclusion of all others, provided ofcourse that the line isidle. (l2) an operator can call any party and cause station to the line to the exclusion of all others even though a conversation between two of the parties' to the line is in progresa (c) a party wishing to talk to any other party on the same line can without rendering the line accessible to any third lparty who may attempt to originate a call render the line ccessible to another whom the operator may be selecting, (d) a station which may be falsely in a calling condition 'can be disabled from interfering with the operation of the line, (e) upon a call being attempted for any such disabled station a distinctive signal can be given. l

A preferred method of carrying our in vention-into effect is to provide at some convenient point, such as at a small local eX- change, a number of connecting relays, one foreach station.. for connecting the stations to the party line. These relayswould be controlled by the line relays of the stations or by a selective device (such as a relay recorder) actuated by the operator at the main exchange. A cut-olf relay would be provided for the usual purpose of cutting out the line relay, and ,a fault relay may be provided for preventing a false calling condition from interfering with the effective operation of the line. Relays would be provided for pert-he connection of his mitting the stations to control the clear-down of a connection until the operator ,shall have taken control of the connection and for thereafter transferring to her the control of the clear-down. The relays may assist in passing supervisory signals from the stations to the main exchange and for tripping the ringing signal when a wanted party answers.

Our invention will now be described .in detail as appliedto such a semi-automatic party line system in which relays only are used but it will be obvious to thosefskilled in the art that the system may work equally well with other apparatus having normally adjacent contacts.

Of the accompanying drawings, Figure l shows two of the party subscribers lines S1 and S3 connected to a common line L.

Figure 2 shows a current'feeding group ABF common to all the subscribers whose lines can be connected to line L. To the right of the feed is shown part of the junction J leading to the main exchange. i

Figure 3 shows the incoming end of the junction at the main exchange, terminating in an operators position. t t

Figure 4L shows a known dialling cord.

Figure 5 shows a modification of a well known relay recorder.

To initiate a call a subscriber S1 lifts his receiver and is immediately connected tothe liunction J via the feed. An ordinary calling lamp GL calls the attention of the operator who thereupon inserts the answering plug of her cord circuit and enquires forl the connec-tion desired.

If the connection desired is other than local one, it is completed in the usual man ner.

lf the connection desired is a local one, the operator asks the calling subscriber to replace his receiver. The subscriber hang. ing up will cause a clear signal to be given to the operator to show her that he has done as requested. This actl does not result in the release of the calling subscribers line froml the junction, the connection being held as long as the operator has the answering plug in the jack.

The operator thereupon inserts the dialling plug DP into the dialling jack DJ and dials the required number. The dialled impulses are received by the recorder which, upon receipt of the complete train, marks the wanted subscriber. The operator then withdraws the dialling plug and inserts the calling plug of the cord circuit and rings the wanted subscriber in any convenient manner.

Both the called and calling subscriber are rung. Upon the called subscriber answering the other bell will stop ringing thus informing the called party that the other party has answered. Conversation may now take place.

The circuit operations will now be de` scribed in detail.

A subscriber S1, Figure 1, upon lifting his receiver closes an energizing circuit 2 for relay LE which in operating closes vcircuit 3 for relays .INC and TCD. Relay JhC operating closes circuit 4l round the calling subscribers line in which relay A1 energizes. Relay A1 operates and closes circuit 5 in which is included relay AIX. Relay AIX in operating closes circuit 6 for relay G to energize. This circuit was prepared by TCD.

It has been assumed that the junction I was free as otherwise G would have been operated and circuit 3 open, so 'that JNC would not have had an energizing circuit.

G in energizing completes energizing circuit 8 for relay CC and also breaks the test wire T, thus breaking circuit 3. JNC is now holding only over the holding circuit 8 and TCD over the following Circuit :-v Battery, winding of relay TCD, contacts 1-3,. TCD-31, (it-8, earth 8. In circuit 8 relay C() `energizes and closes a circuit for relay F. It also opens circuit 2 so that LE de-energizes. ll] hen AIX operated it completed circuit 7 from earth, Figure 3, and the operators line relay CL operates in series with impedance B2, Figure 2. Relay OL closes a lighting circuit for the operators calling lamp CL.

Upon the operator answering the cal-l, which she does in the usual manner by inserting the answering plug of her cord circuit into the answering' jack A, relay B1, Figure 2, operates over circuit 9 which terminates in battery in her cord circuit, which circuit is not shown as it is a well known arrangement.

Relay B1 energizing breaks the circuit just ydescribed of B1-3 and also completes holding' circuit '61 'for Cr.

R lay C is new under operator and the subscriber the connection between hini tion until the plug is wi jack.

will now be seen that should another subscriber on the same party line attempt to initiate a call his relay J NC will not be able to energize because its energizing circuit will be broken at Contact (3f-3. Further as his relay JNC will not energize he cannot oyerhcar the conversation.

To return to subscriber S1 h-e informs the operator the required number and if that number be other than a local number the call is put through in the usual known manner. Suppose, however, the required number be in the same local exchange, the operator asks the calling 'subscriber to hang up his receiver. Such action breaks the loop circuit 4:, thus causing A1 to cle-energize. A1 de-energizing releases circuit 5, causing AIX to cle-energize. AIX deenergizing breaks circuit thus releasing B1, but at the same time an energizing cir cuit is completed 'for relay I which energizes and maintains a holding circuit 62 for Cf. Thus the subscribers connection with the junction J is not released.

Battery no longer being fed through relay B2 to the A junction wire, the supervisory/lamp in the operators cord circuit lights in the usual manner, informing her that the subscriber has hung up. She now inserts her dialling plug DP, Figure 4c, into the dialling jack DJ, Figure 3, thus completing circuit 10. In this circuit are ineluded relay FII), Figure 4, and relay DJC, Figure 8, which energize. The latter relay transfers the junction .I from the answering jack leads to those of the dialling jack.

Battery is thus fed to both the junction wires over circuits 11 and 12, from common negative 11, Figure 3. Circuit 12 passes through relay RP, Figure 2, which .energia-es and locks over its own contacts and the j unction.

Relay NUC, Figure 2, now has an energiz ing circuit over the upper make contacts of Rl. Rel-ay NUC energizes and holds in `2l circuit which includes contacts of relays S X and Cr.

Relay RP energizing closes -circuits 13 and 111-. In circuit 13 relay DCI, Figure 5, energizes. In circuit 14 and its olf shoot circuits 141, 14h, 14, 14d, 111@ relays B50, Beil, B38, B27, B16, energize. These relays in energizing prepare circuit 15 present open at contacts Il. .Circuit 15 finishes at ya heavy broken line on which Yis battery put ron by relay RP. This line will hereinafter be referred to as battery RP.

The 4recorder is now prepared and impulses from the 'operators dial are received over the B junction wire only by relay I, Figure 2. Although relay RP holds over the junction it does not receive impulses as battery is fed to it continuously over the A junction wire from battery 11, Figure 3.

For the purposes vof this example :it will be supposed .that three impulses are sent.

When the B junction wire is broken for the first time relay I cle-energizes and completes circuit 15. M16 energizes and holds over its own contacts a to earth through winding of D02, which energizes and transfers slow release relay DC1 to the impulse wire ITN.

B16 is also transferred to the impulse wire via circuit 15 as far as the contacts of B1.6 thence over contacts 151, winding of BLS. circuit 111 to battery RP.

At the end `of the impulse, when .relay I energizes again, B1.6 vcle-energizes.

At the second break of the B junction wire relay I Vde-energizes M27 energizes over the following circuit :-Circuit 15 as far as contacts. B27-15, thence via contacts BLG-16, M2.7-16, B3.8-16, relay M27 to battery RI).

M27 energizes and holds over its own contacts and outer make contacts of B88.

B27 is now transferred to impulse wire IW circuit 15 as far as the contacts' of B27 thence over contacts B1.6-16, M2.7-15b, winding of B27 circuit 11i to battery RP.

At the end of the impulse, when I energizes again, B27 cle-energizes and breaks the holding circuit of M16 which cle-energizes and re-closes circuits 111 and 141; relay B1.6 energizes again in these two circuits.

At the third break of the B junction wire, I cle-energizes and relay M88 is energized over the following circuitz-Circuit 15 as far as contacts BBB- 15, thence via B27-Vv 17, MSB- 17, Bll-.9-17, relay M88, to battery BI).

M38 energizes and holds over its own contacts and outer make contacts of B119.

B38 is now transferred to the impulse wire IVW, Circuit 15, as far as the contacts of B88, thence over contacts 15C, winding of 133.8, circuit 11i to battery BVI).

At the end of the impulse, when I energizes again, B38 cle-energizes and breaks the holding circuit of MUS, which de-energizes and re-closes circuit 1a and 1er-1; relay B27 energizes again in these c` cuits As no more impulses are sent relay I remains `energized and Acircuit 15 remains broken for a considerable period. D01 now cle-energizes having no holding circuit and completes circuit 18 marking subscriber S8 by energizing relay JNCS. Relay JNCS energizes and holds over its own contacts over a circuit from battery, relay CO3 to earth over make contacts of G. CO3 energizes and in turn energize-s F8. SO which also energized in circuit 18 operated SOX over circuit- 19. SOX holds over its own make contacts and breaks the holding circuit of NUC.

The operator now withdraws her dialling plug, which causes BP to release, this in turn releasing the recorder. She then in serts the calling plug into the calling jack CJ and sends out ringing. current over the A junction line in any known manner. I is kept energized byI the negative return on the BV line.

The bells of both the calling and called subscribers are now`rung.

As soon as one or other of the subscribers answers the loop is again closed and A1 operstes over circuit AIX also operates in circuit 5, cutting out I and putting B1 and coil B2 back into circuit again.

At the end of the conversation as both the subscribers hang up their receivers A1 cle-energizes and consequently AIX also deenergizes.

The supervisory lamp in the cord circuit lights in the usual known manner and the operator takes down the connection thus re- `leasing' B1. G now having no holding circuit releases and breaks the holding circuit 8 which releases (INC, JNGS, CO and COB.

The. feed and junction are thus released and the whole system returned to normal.

For incoming calls from other exchanges forl one of the party lines, the operator inserts her dialling plug, thereby completing circuit 11 in which I energizes. I completes a circuit for G, which energizes and in turn completes circuit 12 for BJP.

The recorder is prepared as before and G Vholds overA the upper contacts of RP while I is impulsing. Y

rEhe operatorthen dials and the wanted subscriber is marked as before. She then inserts her calling plug and rings the wanted subscriber who upon answering energizes A1 which in turn causes AIX to energize and cut out I and RP.

Should an important incoming call for one of the party line subscribers come in while the junction is in use, the operator may force the release by withdrawing the plugs of the cord circuit and then inserting the. dialling plug. (il will Vthen be released. yIhe loop of the subscribers circuit being closed when JNC and CO de-energize, LE will immediately energize. rl`hus F will hold so that circuit 3 will not be closed. .INU cannot operate. The operator may now proceed to call the wanted subscriber in the manner already described.

Should a subscribers line be out-of-order, that is, on his fault relay, his marking wire will be broken and consequently, when he is marked, circuit `18 will not be completed, being open at contacts of rIhe circuit of NUC will not be broken by SQX energizing and when the operator withdraws her dialling plug and substitutes the calling plug, relay BP will release. The release of RP and the energized condition of SOX andv energized condition of NUC complete'a circuit for buzzer NU. (This buzzer has two windings and 1s energized by current in one winding and cle-energized upon operation when current flows in both windings). This buzzer can be heard over the junction by the operator or by a calling subscriber.

FA is a supervisory relay through the winding of which under abnormal conditions the current for certain of the relays is drawn. rlhe relays which may .draw their current through this relay are indica-ted by an asterisk. Am abnormal condition is any condition which causes these relays to draw current when G is not operated.

If G is operated the winding of FA is short-circuited so that .these relays draw current direct. if current is drawn through the winding of FA this relay operates and connects negative to one of the wires of the junction and gives a calling condition. This calling condition can also be given if the fuses which supply battery to the various parts of the exchange should blow. These fuses may be of the lead type'and are indicated in the drawing by Z.

l. A telephone system comprising a main exchange and a sub-centre between which a two wire junction extends, a plurality of two wire subscribers lines terminating at said sub-centre and normally disconnected from the junction, connecting means at the subcentre for connecting any one of the subscribers lines to the junction when such line is a calling line, said connecting means being adapt-ed to be controlled from the main eX- change for connecting` another subscribers line to the junction even though the junction be engaged.

2. A telephone system comprising a plurality of subscribers lines .and a junction from a main exchange over which junction of the subscribers lines can call the said main exchange and over which the main eX- change can `select and call any of the subscribers lines, said subscribers lines being normally disconnected from said junction, characterized in that the junction is provided with connecting` relays equal in number to the number of subscribers lines and with an impulse counting selecting` device by which any of the said relays can be selected and operated to connect the junction :to the line to which said :relay belongs.

A telephone system .according to .claim l in which the junction is provided with a number of sets lof contacts, .one set for each line, and in whicheach line is provided with a set of contacts normally adjacent to the set appropriate to its line but belonging .to .the junction.

A. A telephone system comprising Aa main exchange and a sub-centre between which a two wire junction extends, .a Vplurality of two wire subscribers lines terminating at said sub-centre and normally disconnected from the junction, connecting means Aat the sub-centre for connecting any one ofthe subscribers lines to the junction when such line is a 4calling line, selecting .means whereby .an opeiato` at the main exchange may select and cause the connecting of Athe junction of a second line to the exclusion of all other lines except the one first connected thereto, and controlling means for maintaining in association with the junction the first 'line the said controlli-ng means then being enabled for control by the operator to control the selecting means.

5. A telephone system according to claim Ll in which means is provided whereby a line which falsely simulated a calli-ng line may :be released from the junction and render it free for calls from other lines.

6. A telephone system aocordin-gto'clai-m l, in which means is provided for signalling the main exchange when the apparatus Iat the branch exchange becomes faulty.

7. A telephone system according to claim l in which means is provided for notifying the operator that a wanted line is unavailable, said means including circuit arrangements for notifying any other party who may be connected to the junction that a selected line is unavailable.

in testimony that we claim the foregoing as our invention, we have signed our names this twenty third day of May 1924.

GEORGE l-HENRY BRYANT. BENJAMIN BERTIE J-GHNSON. RCHARD vGRANT `Vl-ANNECK. 

